Test of Auto Dimming Rear View Mirror & How to set "IGN only - No Crank"

[Richard M.]

Yesterday Harry and I were conversing about testing the Auto Dim feature of the mirror. It was 104* heat index here yesterday and I didn't want to open the garage door, so he told me how to IGN on without cranking the engine to turn on everything.

1 - Fob is in car.
2 - Hold bottom of "START" button(normally quick hit for ACC), down for 5-6 seconds(or more) until the dash lights up. HVAC etc may come on too if left on after last shutdown.
3 - Proceed to test away at whatever needs testing.

In this case, we wanted to test the rearview mirror Auto-Dim function without me starting the car.

Here it is, yet another of my Youtube vid's showing it....... versus my typical 1,000,000 words. ....... Rich

[Harry S.]

Re: Test of Auto Dimming Rear View Mirror & How to set "IGN only - No Crank"

Excellent, and you are also a movie star!

[Mark F.]

Re: Test of Auto Dimming Rear View Mirror & How to set "IGN only - No Crank"

Rich or Harry,

Does the blue "N" stand for "night" ?

[Harry S.]

Re: Test of Auto Dimming Rear View Mirror & How to set "IGN only - No Crank"

Rich or Harry,

Does the blue "N" stand for "night" ?

Mark, if I understand your question IGN is for Ignition.

[Mark F.]

Re: Test of Auto Dimming Rear View Mirror & How to set "IGN only - No Crank"

Mark, if I understand your question IGN is for Ignition.

Hi Harry,

No...I meant the blue capital "N" at the top right hand corner of the mirror...

[Harry S.]

Re: Test of Auto Dimming Rear View Mirror & How to set "IGN only - No Crank"

Hi Harry,

No...I meant the blue capital "N" at the top right hand corner of the mirror...

Sorry I misunderstood. That's the compass, Car is pointing North.

[Mark F.]

Re: Test of Auto Dimming Rear View Mirror & How to set "IGN only - No Crank"

Sorry I misunderstood. That's the compass, Car is pointing North.

LOL...I shoulda been able to figure that out...more coffee on its way

[Harry S.]

Re: Test of Auto Dimming Rear View Mirror & How to set "IGN only - No Crank"

LOL...I shoulda been able to figure that out...more coffee on its way

Yep, I'm on my 4th cup of high test.

[Richard M.]

Re: Test of Auto Dimming Rear View Mirror & How to set "IGN only - No Crank"

I've been up since 2:15 I'm way aheeeeaaad of you guys.lol

Harry, BTW, That left side on/off(0-1) switch is for the compass on or off. But if it's held in for several seconds, it disables Auto-Dim and the green indicator Lamp goes out. I bet it's in the Owners Manual somewhere.

Yesterday I also tested the Reverse Light effect on Auto-Dim. Putting car in Reverse will disable it. Makes sense as if backing into a spot that is lit behind you, it would otherwise be too dark to see behind you.

Another test I did was to pull the REVERSE LAMP fuse in the Pass side footwell fuse panel. This disabled Auto-Dim. The BCM talks to the mirror and provides the Reverse Lamp signal to the mirror, activating logic inside the mirror to disable it. If no signal(fuse pulled or malfunction from the BCM) Auto-Dim won't work.
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Additionally, the mirror logic also controls the Driver Side outside rearview mirror dimming function, via the interior mirror forward sensor(day/night), as well as the rearward "look behind for brights" sensor . So if the interior mirror is defective, the outside mirror will likely not Dim either, depending on the fault source inside the mirror digital logic circuitry.

Rich
P.S. Here are some CSM pages describing functions and a wiring reference.

[Ed H.]

Re: Test of Auto Dimming Rear View Mirror & How to set "IGN only - No Crank"

To all who are following this thread, I found an anomaly during my PV 2 weeks ago. If I stopped the car with the motor running and applied the parking brake, both side view mirror's would automatically turn down to allow one to see the white lines when reversing into a parking spot. Go figure.

[Richard M.]

Re: Test of Auto Dimming Rear View Mirror & How to set "IGN only - No Crank"

To all who are following this thread, I found an anomaly during my PV 2 weeks ago. If I stopped the car with the motor running and applied the parking brake, both side view mirror's would automatically turn down to allow one to see the white lines when reversing into a parking spot. Go figure.

"Automatic Tilt Mirrors"

As a follow up to future curiosity seekers, Ed and Harry and I conversed about this last week. I found nothing in my 2007 Owners Manual, nor did I find reference to this function in my 2007 Corvette Service Manuals.

Many GM vehicles today have the option in their DIC programming or APP programming to "Tilt Mirrors in Reverse".

Allegedly, the the "Reverse Mirror Tilt" was to be available in production but the idea was scrapped at some point. Ed's car is #53 off the assembly line, and if the first 50 cars were deemed as prototypes, his was very close behind.

His car has this "Feature", or a facsimile of it, as his mirrors tilt when the Park Brake is applied.

It is unknown if any cars after his has this feature or not.

Rich